Concerns about global climate change resulting from greenhouse gas emissions has resulted in large scale efforts to reduce the use of energy, in order to thereby reduce greenhouse gas emissions associated with the generation and use of the energy. In one example in 2007 the United States of America mandated an energy efficiency increase of 30 percent for light bulbs by 2012. One common method of increasing lighting efficiency is replacing incandescent light bulbs (ILB's) with compact fluorescent lights (CFL's) and light emitting diodes (LED's), as each are more efficient sources of light, using less electricity to generate comparable levels of ILB light.
Fluorescent lights generally contain the element mercury, and CFL's typically contain several milligrams of mercury. At room temperature, mercury is a liquid that has a high vapor pressure. The mercury is vaporized further when an electrical discharge is initiated within the bulb, and it is the excitation of mercury atoms which produces the light emitted by fluorescent light bulbs.
Mercury vapor is toxic to humans, and concerns arise with the safe handling and disposal of CFL's and other fluorescent lights. More particularly it has been determined that elemental (metallic) mercury causes negative health effects when breathed as a vapor and absorbed through the lungs. Such exposures can occur when elemental mercury is spilled or products that contain elemental mercury break and expose mercury to the air, particularly in warm or poorly-ventilated indoor spaces. Health effects from exposure to mercury may include tremors, emotional changes (e.g., mood swings, irritability, nervousness and excessive shyness), insomnia, neuromuscular changes (e.g. weakness, muscle atrophy, twitching), headaches, disturbances in sensations, changes in nerve responses, performance deficits on tests of cognitive function, damage to kidneys, respiratory failure, and death.
During normal fluorescent light operation, liquid mercury and mercury vapors are contained within the bulbs, and exposure to mercury becomes a concern in the event of breakage of a fluorescent light and in the disposal of a no-longer functioning light. Mercury vapor produced by spilled mercury is a danger to human beings and animals, particularly within enclosed areas such as homes and offices, and mercury spills may be difficult and expensive to abate and clean up. Difficulties in safely and economically disposing of CFL's, as well as fears of potential exposure to toxic mercury therein, have limited public acceptance of the CFL as a replacement for incandescent light bulbs, thereby hampering efforts to reduce household energy usage for lighting tasks and associated greenhouse gas emissions.